>>3972058This one imo
3D relationships tend to fade over time because people get complacent, work takes up more of their time, and the "honeymoon" phase ends with neither partner trying to take up the slack
In a 2D relationship, the only one that can pull is you. There's no shame in not being able to maintain that forever and your waifu would completely understand.
If there's nothing you can do to salvage those feelings, at the very least remember your time with her as a happy one; don't sour what you had together.